Short sellers borrowed an additional 1.7M shares of Viking Therapeutics (VKTX) over the past week as the stock rallied 15% following Gilead Sciences' (GILD) failure in nonalcoholic steatohepatitis, Bailey Lipschultz of Bloomberg reports, citing data from S3 Partners. More than 43% of Viking shares available for trading are now sold short, the highest in at least a year, according to data compiled by S3.

Bullish option flow detected in Viking Therapeutics with 7,123 calls trading, 4x expected, and implied vol increasing over 5 points to 124.15%. Mar-19 9 calls and Mar-19 10 puts are the most active options, with total volume in those strikes near 5,700 contracts. The Put/Call Ratio is 0.18. Earnings are expected on March 13th.

Bullish option flow detected in Viking Therapeutics with 5,450 calls trading, 2x expected, and implied vol increasing almost 17 points to 122.82%. Mar-19 10 calls and May-19 10 calls are the most active options, with total volume in those strikes near 2,900 contracts. The Put/Call Ratio is 0.20. Earnings are expected on March 13th.

Bullish option flow detected in Viking Therapeutics with 5,863 calls trading, 6x expected, and implied vol increasing almost 12 points to 99.25%. Feb-19 9 calls and Mar-19 9 calls are the most active options, with total volume in those strikes near 2,400 contracts. The Put/Call Ratio is 0.08. Earnings are expected on March 13th.